Neil, Thank you for this. I am really happy to see that this is finally happening...for a long time the EBM camp has not talked to decision-making researchers, and I hope this will finally open the long neglected discussion between evidence and decision-making (necessary but not sufficient for decision-making)...This also provides the opportunity to re-define EBM. Most textbook definitions of EBM still talk about ‘‘integration of best research evidence with clinical expertise and patient values.’’ Based on theoretical ground that Neil alluded to this is not possible. Most decision scientists would argue that no theory can be both descriptively and normatively (and prescriptively) valid. Hence, definition of EBM aiming to achieve the stated goals of ‘‘integration of best research evidence with clinical expertise and patient values" is theoretically impossible: integration of normative concepts (evidence and patient values) with descriptive theories of decision making (clinical expertise) to become a prescriptive theory (improve decision making) cannot be done (at least at today's level of scientific development and as long as humans think the way they do...).
Which is not to say that there is no much to improve how we practice medicine... but we need to know what we can and cannot do...
Benjamin Djulbegovic, MD, PhD
Professor of Medicine and Oncology
University of South Florida & H. Lee Moffitt Cancer Center & Research Institute
Co-Director of USF Clinical Translation Science Institute
Director of USF Center for Evidence-based Medicine and Health Outcomes Research
USF Health Clinical Research
12901 Bruce B. Downs Boulevard, MDC02
Tampa, FL 33612
Phone # 813-396-9178
Fax # 813-974-5411
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From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Maskrey Neal
Sent: Wednesday, July 08, 2009 12:41 PM
To: [log in to unmask]
Subject: Re: List of biases
Thanks for starting this string Jon. We've discussed the importance of how human beings, clinicians and patients and both together, acquire and use information to reach decisions in health care in the past and you've finally prompted me to tap to this group.
Apologies for the length of this. I've kept it as short as I can, and tried though failed to avoid stating the obvious. No doubt you'll tell me.
Ian Scott has an excellent paper in the 4 July BMJ - "Errors in clinical reasoning: causes and remedial strategies". For those interested, two easy-reads as introductions to the topic are Gerd Gigerenzer's "Gut Feelings" and Stuart Sutherland's "Irrationality: the enemy within".
I'll summarise. There are essentially two systems we use in acquiring information and reaching a decision. So this is any decision, including in health care decisions both diagnosis and management. A system 1 approach involves acquiring a limited number of information items and using them to make a "fast and frugal decision". The human brain has limited capacity and we need to truncate the volume of information and process it in order to be able to make a decision.
System 2 is more systematic with lengthy and detailed collection and analysis of data. If we were buying a new car we'd almost certainly read some magazine articles and talk to some people who we trusted for the knowledge about cars. I'd guess almost no one would go to the systematic reviews re automotive engineering on the Society of Automotive Engineers website. And if we did, that might not improve the decision.
System 2 is what we'd expect to underpin health care decisions, especially those big decisions that don't thankfully have to be made more than a few times in a lifetime. Unfortunately the data shows that clinicians make decisions based on brief reading and talking to other people (Gabby and le May BMJ 2004). That sounds uncomfortable but there's some reassurance in that Gigerenzer shows in some settings system 1 based decision making can out perform system 2 based decision making.
However, that seems less credible in more complex decisions and the list of cognitive biases described in the literature looks like testimony to the fallibility of humans.
Obviously its not a simple as the above and e.g. the recent BMJ paper describing GP reasoning from Carl Henegan et al provides more complexity and insights.
So what's to be done. Well, firstly we've recognised the issue. Secondly, it seems sensible to explore teaching some of this in our work. Ian Scott summarises the evidence for that and as you'd expect it looks like its a slim volume as yet. There might be some harms from taking this too far too soon, but we are all too aware of the greater harms from the under and over implementation of health care interventions.
For me this links into where we're going with EBM. I think we're in the 3rd age and tip-toeing into the 4th. EBM v1.0 was conceptual. EBM v2.0 was and is technical development - searching skills, MA stats etc. EBM v3.0 was and is the industrial age - Cochrane collaboration, teaching critical appraisal to anyone who shows interest etc. And so I'd profer that if we want to make EBM really live for people (cf threads on this group on a number of occasions) EBM v4.0 needs to be Customer Focussed. The customers are clinicians, patients, commissioners and no doubt others. And if we want to reach those groups we need to think about they as humans use EBM outputs as information and how they use those to make decisions. People need to be careful who they talk to and what they (briefly) read.
And in order to broaden our understanding of why high quality evidence still doesn't get incorporated into practice quickly, we need to have a dialogue with other specialties - sociologists, ethicists and as in this area the cognitive psychologists.
In summary, we teach health care professionals so they can make decisions. It seems perverse not to describe to them how they as human beings make decisions - so they at least stand some chance of being aware of some of their own and others potential foibles, doesn't it?
There's a few of us who've produced (at last) 5 papers which include the above and lots more. They've been accepted by the UK RCGP journal for GP Registrars InnovAiT and are in press. I'll post links as and when they appear.
Love to talk to people about this.
Director of Evidence Based Therapeutics
National Prescribing Centre
From: Evidence based health (EBH) <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Wed Jul 08 07:38:24 2009
Subject: List of biases
I thought I'd share this fascinating list of cognitive biases found on wikipedia http://en.wikipedia.org/wiki/List_of_cognitive_biases.
What struck me was two things:
1) The sheer volume of potential cognitive biases
2) We often focus on methodological biases, but irrespective of the purity of methodology, there is still a mountain to climb when it comes to overcoming cognitive bias.
PS I feel the need to play a game of cognitive bias bingo!